Hairsetting compositions

ABSTRACT

Hairsetting compositions comprise as film-formers copolymers based on tert-butyl acrylate or tert-butyl methacrylate having a K value of from 10 to 50 which are obtainable by free-radical polymerization of 
     A) from 30 to 72% by weight of tert-butyl acrylate or tert-butyl methacrylate or a mixture thereof as monomer A, 
     B) from 10 to 28% by weight of acrylic acid or methacrylic acid or a mixture thereof as monomer B, and 
     C) from 0 to 60% by weight of a free-radically copolymerizable monomer or of a free-radically copolymerizable monomer mixture as monomers C, where at least one of the monomers C produces a homopolymer having a glass transition temperature of less than 30° C., 
     the carboxyl groups of the copolymers being partially or completely neutralized.

The present invention relates to novel hairsetting compositions whichcomprise as film-formers copolymers based on tert-butyl acrylate ortert-butyl methacrylate having a K value of from 10 to 50 and which areobtainable by free-radical polymerization of

A) from 30 to 72% by weight of tert-butyl acrylate or tert-butylmethacrylate or a mixture thereof as monomer A,

B) from 10 to 28% by weight of acrylic acid or methacrylic acid or amixture thereof as monomer B, and

C) from 0 to 60% by weight of a free-radically copolymerizable monomeror of a free-radically copolymerizable monomer mixture as monomers C,where at least one of the monomers C produces a homopolymer having aglass transition temperature of less than 30° C.,

the carboxyl groups of the copolymers being partially or completelyneutralized.

EP-A 379 082 discloses hairsetting compositions which comprise asfilm-formers copolymers based on tert-butyl acrylate and/or tert-butylmethacrylate having a K value of from 10 to 50, which are obtainable byfree-radical polymerization of

A) from 75 to 99% by weight of tert-butyl acrylate and/or tert-butylmethacrylate,

B) from 1 to 25% by weight of acrylic acid and/or methacrylic acid, and

C) from 0 to 10% by weight of a further free-radically copolymerizablemonomer,

the carboxyl groups of the copolymers being, as usual, partially orcompletely neutralized by amines.

Parameters of these prior-art compositions which are still in need ofimprovement, however, are the ease of washoff of the polymer from thehair, the solubility of the film-former in aqueous formulations, whichare nowadays increasingly displacing those formulations based solely onorganic solvents which are ecologically acceptable, and the handle andset of the treated hair, since hair which is treated with the prior-arthairsetting compositions generally feels too brittle or too coarse.

It is an object of the present invention to prepare a hairsettingcomposition which no longer has the abovementioned disadvantages.

We have found that this object is achieved by the hairsettingcompositions defined at the outset.

The monomer or monomers C serve to modify the properties of thecopolymer. In a preferred embodiment, monomers used are C₁-C₁₈-alkylacrylates or methacrylates, especially C₁-C₄-alkyl acrylates ormethacrylates, or a mixture of these (meth)acrylates withN-C₁-C₁₈-alkylacrylamides or -methacrylamides, especiallyN—C₁-C₄-alkylacrylamides or -methacrylamides. In these (meth)-acrylatesand (meth)acrylamides, C₁-C₄-alkyl is suitably methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl.

Particularly good results are obtained when C comprises un-branchedC₂-C₄-alkyl acrylates, alone or as a mixture with branchedN—C₃-C₄-alkylacrylamides. Particular preference is given to the use forthis purpose of ethyl acrylate or of a mixture of ethyl acrylate andN-tert-butylacrylamide.

In a preferred embodiment, the composition of the copolymer used asfilm-former is

A) from 50 to 72% by weight, in particular from 60 to 70% by weight, ofmonomer A,

B) from 12 to 25% by weight, in particular from 15 to 23% by weight, ofmonomer B, and

C) from 3 to 38% by weight, in particular from 7 to 25% by weight, ofmonomer C.

The upper limit of 72% by weight for monomer A is particularly criticalsince above this limit the advantageous properties of the hairsettingcomposition of the invention are no longer found. The marked change inthe spectrum of properties of the hairsetting composition between acontent of 72 and 75% by weight of monomer A was surprising inparticular in the context of the compositions from EP-A 379 082.

In a further preferred embodiment, the copolymer used as film-former iscomposed of

A) tert-butyl acrylate as monomer A,

B) methacrylic acid as monomer B, and

C) ethyl acrylate or a mixture of ethyl acrylate andN-tert-butylacrylamide as monomer C.

The copolymers described are prepared in a known manner by free-radicalcopolymerization of the monomers A, B and, if used, C. The reaction iscarried out by the usual polymerization techniques, for example by themethods of suspension, emulsion or solution polymerization.

The polymerization reaction, which proceeds by a free-radical mechanism,is initiated by the customary peroxo or azo compounds, for exampledibenzoyl peroxide, tert-butyl perpivalate, tert-butylper-2-ethylhexanoate, di-tert-butyl peroxide, tert-butyl hydroperoxide,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, alkali metal persulfates orammonium persulfates, azobisisobutyronitrile, hydrogen peroxide or redoxinitiators, advantageously in amounts of from 0.1 to 2% by weight, basedon the weight of the monomers. The amounts of monomers and solvents ordispersants are advantageously chosen so as to give from 30 to 80%strength by weight solutions or dispersions, or suspensions, of thecopolymers. The content of residual monomer can be reduced bypostpolymerization in accordance with generally known methods.

The copolymers have K values of from 10 to 60, preferably from 15 to 40.The particular K value desired can be established in a manner known perse by appropriate choice of the polymerization conditions, such as thetemperature of polymerization and the concentration of initiator. Ifdesired, especially when employing emulsion and suspensionpolymerization, it may be appropriate to use regulators, especiallysulfur compounds such as mercaptoethanol, 2-ethylhexyl thioglycolate,thioglycolic acid or dodecylmercaptan, in order to reduce the K value.The K values are measured in accordance with Fikentscher,Cellulosechemie, Vol. 13 (1932) 58 to 64 at 25° C. in 1% strength byweight ethanolic solution and are a measure of the molecular weight.

Such copolymers normally have glass transition temperatures of between50 and 130° C., in particular between 60 and 100° C.

When the hairsetting composition is prepared by emulsion polymerizationthe resulting dispersion can be either incorporated directly into anaqueous hairsetting formulation or dried, for example by spraydrying, sothat the hairsetting composition can be processed and used in powderform.

For use in the hairsetting compositions of the invention, the carboxylgroups of the copolymers thus obtained are usually neutralized with analkali metal hydroxide or, preferably, with an amine, partially orcompletely, advantageously to the extent of from 5 to 100%, preferablyfrom 30 to 95%. Neutralization is preferably carried out with

a mono-, di- or trialkanolamine having 2 to 5 carbon atoms in thealkanol radical, which may be in etherified form, for example mono-, di-and triethanolamine, mono-, di- and tri-n-propanolamine, mono-, di- andtriisopropanolamine, 2-amino-2-methylpropanol anddi(2-methoxyethyl)amine,

an alkanediolamine having 2 to 5 carbon atoms, for example2-amino-2-methyl-1,3-propanediol and 2-amino-2-ethyl-1,3-propanediol, or

a primary, secondary or tertiary alkylamine having a total of 5 to 10carbon atoms, for example N,N-diethylpropylamine.

Particularly good results are obtained with 2-amino-2-methylpropanol,triisopropanolamine and 2-amino-2-ethyl-1,3-propanediol.

Particularly suitable alkali metal hydroxides for the neutralization aresodium hydroxide and potassium hydroxide.

The hairsetting compositions according to the invention are employed,for example, as gels, lotions, mousses and, in particular, ashairsprays. Particularly preferred hairspray formulations are thosecomprising the following constituents:

from 0.1 to 20% by weight, preferably from 0.5 to 10% by weight, inparticular from 2 to 10% by weight, of the partially or completelyneutralized copolymer

from 1 to 99.9% by weight, preferably from 5 to 50% by weight, inparticular from 10 to 40% by weight, of water

from 0 to 95% by weight, preferably from 20 to 60% by weight, inparticular from 25 to 50% by weight, of a customary organic solvent suchas, in particular, ethanol, isopropanol or dimethoxymethane, or elseacetone, n-propanol, n-butanol, 2-methoxy-1-propanol, n-pentane,n-hexane, cyclohexane, n-heptane, n-octane or dichloromethane, or amixture thereof

from 0 to 90% by weight, preferably from 30 to 80% by weight, inparticular from 45 to 70% by weight, of a customary propellant such aspropane, n-butane, isobutane, 2,2-dimethylbutane, n-pentane, isopentane,dimethyl ether, difluoroethane, fluorotrichloromethane,dichlorodifluoromethane or dichlorotetrafluoroethane, or a mixturethereof.

Compounds from the above especially employed as propellants are thehydrocarbons, especially propane, n-butane, n-pentane and mixturesthereof, and also dimethyl ether and difluoroethane. If desired, one ormore of the abovementioned chlorinated hydrocarbons can be used as acomponent of propellant mixtures, but only in a minor proportion, forinstance up to 20% by weight based on the propellant mixture.

The hairsetting compositions according to the invention are alsoparticularly suitable for pump spray formulations without the additionof propellants, and for aerosol sprays with customary pressurized gases,such as nitrogen, compressed air or carbon dioxide as propellants.

These spray formulations may additionally contain minor amounts ofperfume oils, for example from 0.1 to 0.5% by weight.

A standard aqueous spray formulation has, for example, the followingcomposition:

from 2 to 10% by weight of the copolymer 100% neutralized with2-amino-2-methylpropanol

from 10 to 76% by weight of ethanol

from 2 to 40% by weight of water

from 10 to 40% by weight of dimethyl ether

The copolymers present in the novel hairsetting compositions are notablefor their high degree of compatibility with the apolar propellants inspray formulations, especially with hydrocarbons such as propane,n-butane or mixtures thereof. They give a good hairsetting effect, whichis evident from the high values for curl retention which are usuallyabove 80% in this context. The compositions are also notable for causingalmost no sticking of the hair.

However, it is in those applications-related properties which weredesignated as being in need of improvement, when discussing theprior-art compositions at the outset, that the novel hairsettingcompositions show particularly outstanding results. In alcohols such asethanol or isopropanol and in mixtures of these alcohols with water,they give clear solutions. The clarity of the solutions is retained evenif the solutions are employed in standard spray formulations togetherwith propellants such as dimethyl ether. The novel hairsettingcompositions can be washed out of the hair very readily. Hair treatedwith them is of heightened sleekness and has a pleasant natural handle.At the same time, the setting effect achieved is high, so that it ispossible in principle to reduce the requisite amount of film-former inthe hairspray formulation.

In order to tailor the properties of hairsetting compositions it can beadvantageous to employ the copolymers of the invention as a mixture withother hairsetting polymers. Further suitable hairsetting polymers arecommercially available polymers such as polyvinylpyrrolidones,copolymers of vinylpyrrolidone and vinyl acetate, copolymers of vinylacetate and crotonic acid, copolymers of vinyl acetate, vinyl propionateand crotonic acid or copolymers based on acrylate/acrylamide. Suchmixtures can contain the copolymers of the invention and the otherhairsetting polymers in a weight ratio of from 1:99 to 99:1.

EXAMPLES

Preparation instructions for Examples 1 to 15 and Comparison Examples Ato D

Example 2 (Emulsion Polymerization)

1 g of sodium lauryl sulfate, 6.7 g of a commercial nonionic emulsifier,100 g of water, 1.3 g of ethylhexyl thioglycolate, 60 g of methacrylicacid, 210 g of tert-butyl acrylate and 30 g of ethyl acrylate were usedto prepare an emulsion which was metered at from about 75 to 85° C. overthe course of from about 2 to 4 hours, in the course of thepolymerization, into a polymerization vessel containing 500 g of water.The initiator, a solution of 1 g of sodium persulfate in 100 g of water,was likewise run in continuously during the polymerization. In order toreduce the content of residual monomer, a redox initiator (tert-butylhydroperoxide/ascorbic acid) was subsequently added and the mixturesubjected to postpolymerization.

The preparation of Examples 1, 3 to 11 and A to D was analogous to thatof Example 2.

Example 12 (Solution Polymerization)

A mixture of 105 g of tert-butyl acrylate, 30 g of ethyl acrylate, 15 gof acrylic acid, 0.5 g of tert-butyl perpivalate and 25 g of ethanol washeated to 75° C. After the commencement of polymerization, which wasevident from an increase in viscosity, a mixture of 945 g of tert-butylacrylate, 270 g of ethyl acrylate, 135 g of acrylic acid and 270 g ofethanol, and a solution of 6.0 g of tert-butyl perpivalate in 90 g ofethanol, were added simultaneously over the course of 6 hours, themixture being maintained at a gentle boil at from 77 to 80° C. Asolution of 3.0 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in 400g of ethanol was then added, after which the reaction vessel was sealedpressure-tight, heated to 130° C. and maintained at this temperature for3 hours. The polymer content of the resulting solution was adjusted to50% by weight with about 550 g of ethanol. The terpolymer had a K valueof 32.5 (measured in 1.0% strength ethanolic solution at 25° C.).

The preparation of Examples 13 and 14 was analogous to that of Example12.

Example 15 (Suspension Polymerization)

70 g of tert-butyl acrylate, 12 g of ethyl acrylate and 18 g ofmethacrylic acid were heated in succession to 70° C. with stirring in250 g of water containing 0.9 g of polyacrylic acid of molecular weight250,000, 1 g of a commercial emulsifier based on a paraffinsulfonatemixture having an average chain length of 14 to 15 carbon atoms and 0.3g of 2-mercaptoethanol as regulator. 0.02 g of tert-butylper-2-ethylhexanoate was then added in small portions. After the finalportion of initiator had been added, polymerization was continued tocompletion at 90° C. for 3.5 hours more. Steam was then passed throughat 100° C. until about 300 g of water had distilled over in the courseof 4 hours, with complete removal of residual monomer. The resultingpolymer suspension was filtered, washed with water to remove very fineundissolved particles, and dried in a stream of air at about 50° C. togive a flowable powder having average particle sizes of from 0.3 to 1.5mm. The K value was 40 (measured 1% strength by weight solution inethanol).

Application Properties

The table below gives the figures for the composition, curl retention,ease of washoff, solubility, handle and setting effect of Examples 1 to15 and of Comparison Examples A to D.

The curl retention is a measure of the hairsetting effect under extremeclimatic conditions. It is measured in a model test on locks of hairtreated by producing a customary water-wave on hair about 15 cm long andsprayed with the respective spray formulation from a distance of 10 cmfor 4 seconds. After the locks had spent 5 hours suspended in aclimate-controlled chamber at 25° C. and 90% relative atmospherichumidity, the relative deformation (extension) of the locks, based ontheir original shape, is determined. A high value denotes a high settingeffect, ie. at 100% the original shape was retained completely.

The ease of washoff of the polymer from the hair, the handle (the feelof the treated hair) and the setting effect (the strength of the settingof hair on a headform) were each rated on a scale of 1 to 5, where

1=very good

2=good

3=still acceptable

4=poor

5=very poor

The solubility of the polymer to give a clear solution was assessed in amixture of ethanol, water and polymer in a weight ratio of 55:40:5, asfollows:

+=clear solution−=cloudy

All measurements and ratings were determined using a customary, standardspray formulation in which the copolymer was 100% neutralized with2-amino-2-methylpropanol.

Key to table

TBA = tert-butyl acrylate MAA = methacrylic acid AA = acrylic acid EA =ethyl acrylate TBAA = N-tert-butylacrylamide

TABLE Composition and applicational properties of Examples 1 to 11 andof Comparison Examples A to D Composition Curl Ease of Setting Ex. [% byweight] retention washoff Solubility Handle effect No. TBA MAA AA EATBAA [%] [rating] [+/−] [rating] [rating] 1 72 18 — 10 — 84 2 + 2 2 2 7020 — 10 — 88 2 + 1 1 3 60 20 — 20 — 84 1 + 1 1 4 58 22 — 20 — 73 1 + 2 25 50 20 — 20 10 88 2 + 2 2 6 60 20 — 10 10 79 2 + 1 1 7 40 25 — 25 10 761 + 2 2 8 65 20 — 5 10 80 1 + 1 1 9 65 15 — 10 10 82 2 + 1 1 10 35 20 —20 25 66 1 + 1 1 11 40 20 — 20 20 75 1 + 1 1 12 70 — 10 20 — 79 2 + 1 113 65 15 — 20 — 77 3 + 1 2 14 70 20 — 10 — 89 1 + 1 1 15 70 18 — 12 — 842 + 1 1

Curl Ease of Setting Ex. Composition [% by weight] retention washoffSolubility Handle effect No. TBA MAA AA EA TBAA [%] [rating] [+/−][rating] [rating] for comparison: A 85 15 — — — 89 4 − 5 5 B 75 25 — — —85 1 + 5 5 C 75 15 — 10 — 86 4 − 3 3 D 75 20 —  5 — 84 2 + 3 3

We claim:
 1. A hair setting composition comprising as film-formerscopolymers consisting essentially of tert-butyl acrylate or tert-butylmethacrylate having a K value of from 10 to 50 which are obtained byfree-radical polymerization of monomers consisting of A) from 50 to 72%by weight, based on the total weight of monomers employed in thepolymerization, of tert-butyl acrylate or tert-butyl methacrylate or amixture thereof as monomer A, B) from 12 to 25% by weight, based on thetotal weight of monomers employed in the polymerization, of acrylic acidor methacrylic acid or a mixture thereof as monomer B, and C) from 3 to38% by weight, based on the total weight of monomers employed in thepolymerization, of a free-radically copolymerizable monomer capable offorming a homopolymer having a glass transition temperature of less than30° C., which monomer is ethyl acrylate, wherein any carboxyl groupspresent in the copolymer are partially or completely neutralized.
 2. Ahairsetting composition in the form of a spray formulation comprising,in addition to solvents for such formulations and, optionally,propellants, from 0.1 to 20% by weight of a copolymer as in claim
 1. 3.A hairsetting composition as claimed in claim 1, additionally comprisingother polymers which are suitable for setting hair.